title: Dynamic evolution of rht-1 homologous regions in grass genomes.
abstract: Hexaploid bread wheat contains A, B, and D three subgenomes with its well-characterized ancestral genomes existed at diploid and tetraploid levels, making the wheat act as a good model species for studying evolutionary genomic dynamics. Here, we performed intra- and inter-species comparative analyses of wheat and related grass genomes to examine the dynamics of homologous regions surrounding Rht-1, a well-known "green revolution" gene. Our results showed that the divergence of the two A genomes in the Rht-1 region from the diploid and tetraploid species is greater than that from the tetraploid and hexaploid wheat. The divergence of D genome between diploid and hexaploid is lower than those of A genome, suggesting that D genome diverged latter than others. The divergence among the A, B and D subgenomes was larger than that among different ploidy levels for each subgenome which mainly resulted from genomic structural variation of insertions and, perhaps deletions, of the repetitive sequences. Meanwhile, the repetitive sequences caused genome expansion further after the divergence of the three subgenomes. However, several conserved non-coding sequences were identified to be shared among the three subgenomes of wheat, suggesting that they may have played an important role to maintain the homolog of three subgenomes. This is a pilot study on evolutionary dynamics across the wheat ploids, subgenomes and differently related grasses. Our results gained new insights into evolutionary dynamics of Rht-1 region at sequence level as well as the evolution of wheat during the plolyploidization process.
authors.affiliation: Key Laboratory of Crop Germplasm Resources and Utilization, Ministry of Agriculture, the National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, the Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.forename: Xiuying
authors.initials: X
authors.lastname: Kong
authors.forename: Chao
authors.initials: C
authors.lastname: Shi
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Gu
authors.forename: Cuiyun
authors.initials: C
authors.lastname: Jin
authors.forename: Lizhi
authors.initials: L
authors.lastname: Gao
authors.forename: Jizeng
authors.initials: J
authors.lastname: Jia
mesh_terms: D017124:Conserved Sequence / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D019143:Evolution, Molecular; D018745:Genome, Plant / Q000235:genetics*; D010865:Pilot Projects; D010940:Plant Proteins / Q000235:genetics*; D006109:Poaceae / Q000235:genetics*; D011123:Polyploidy; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000379:methods; D017385:Sequence Homology; D014908:Triticum / Q000235:genetics*
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins; C120413:RHT-D1A protein, Triticum aestivum